1. Field of the Invention
This invention relates to microwave devices, and more particularly to electromechanical multiposition coaxial switches with angularly spaced radial channels and internal termination.
2. Description of the Prior Art
Pertinent prior art pertaining to the present invention is described in U.S. Pat. No. 3,182,270 by Russell E. Horton entitled "Multiple Position Coaxial Switch With Angularly Spaced Radial Channels." Therein Horton recites a central cylindrical cavity 12 with a contact disc 22 therein mounted on the inner conductor 16 of a central coaxial connector 14, and a plurality of termination resistors 31 above and in close unshielded proximity to the cavity 12. He further recites a plurality of cantilevered reeds 23 fixed to and extending from inner conductors 17 of peripheral connectors 15 to the disc 22. The resistors are designed to terminate the peripheral connectors with an impedance match when in contact with the reeds. Horton also recites a series of relay activated leaf springs whose pressure is used to break the termination.
At least two problems present themselves from such a configuration: reliability and isolation. The reliability of the switch will depend on how long the reeds will last before they break at their fixed position on the peripheral connectors, and/or how long the leaf springs will last. The reeds and leaf springs, after all, constitute cantilevered springs as shown, and bear tension at their fixed points. The problem of isolation arises from the close unshielded proximity of the termination resistors to the central connector.
The general state of the art, apart from the present invention, provides switches with 8 positions or less, a frequency range from DC to essentially 3 gigahertz (ghz), a maximum VSWR (voltage standing wave ratio) of essentially 1.6:1 or higher, an isolation of essentially 30 DB or less, and an overall outer diameter of greater than essentially 31/2 inches.
The present invention improves significantly on these various parameters by a novel arrangement of features and parts and extends the state of the art significantly as further discussed below.